What Is A Leach Field?

Last Updated On May 23, 2024

Updated on September 14, 2022



Reviewed by

What is a Leach vs Drain Field

Our septic system consists of three main parts; the septic tank, the pipes, and the leach field. 

This leaves us with one question. What is a leach field?

For any septic system to work right, it requires a septic leech field. In our yards, adjacent to the septic tanks, lay an underground array of perforated pipes.

The liquids filter through the leach lines for contaminants to fully dissipate after the solids from our wastewater is digested in the septic tank. The solid waste will remain at the bottom of our septic tank. The remaining liquids, also called effluent, get filtered by the soil.

What's In This Guide?

      What Is The Difference Between A Septic Tank And A Leach Field?

      Everyone’s heard of a septic tank. You might even have one. So we might wonder, what is the difference between a septic tank and a leach field? 

      The main difference between a septic tank and a septic drain field is this. The tank portion takes care of solids while the field filters the remaining liquid. 

      How does the drain field work? The waste initially flows from our home, through the main sewer pipe, to our septic tank. Solids drop to the bottom of the tank, where bacteria begin to break them down. The solids will stay at the bottom of the tank until they completely decompose or we get our tank pumped. 

      The leach field is also known as a leaching bed, absorption field, or filter bed. It consists of large PVC pipes with holes drilled into the sides like filters. 

      During construction, these pipes lay on a bed of gravel and sand before they get back filled with dirt. As the liquid waste rises to the top of our septic tank, it flows freely down to be absorbed naturally into the earth. This is called a gravity-fed system, although some systems use a pump as well.

      What Is The Purpose Of A Leach Field?

      Estimates say 60 million Americans use a private septic system. If you’re not located near a public sewer system or waste treatment facility, this is your only option.

      The main purpose of the leach field is to serve as the final stage of “treatment” before the water flows back into groundwater sources.

      Still, others prefer a private system and seek it out in order to be “off-grid” and for savings. As homeowners, we’re always looking for new ways to save a few bucks, especially on utility bills. Our sewer bill is no different.

      Raw sewage is not something any homeowner ever wants to deal with. If we can find a way to dispose of it more efficiently, we use it. 

      Filtering the liquid contaminants from our sewage saves a fortune over time, especially if you use a treatment product regularly and avoid frequent pumping costs. It also removes the impurities from the water in an environmentally friendly way. 

      Septic Leach Field Explained

      Anything that goes down our drains ends up in our septic tank. Everything we flush needs to be able to decompose properly. Our septic tank works by using the decomposition process. 

      The sewage enters the septic tank near the top of the tank itself.  As it fills up, the solids remain at the bottom of the tank, where bacteria begin to break them down. The solids stay at the bottom and turn into sludge. 

      Our tank continues to rise as we continue to flush. When it gets to the top, liquids then seep out. The wastewater flows into the leach field. As the solids stay as sludge at the bottom of our septic tank to break down and eventually get pumped out, the liquid contaminants can naturally filter through the drain field buried in our yard.

      What Is The Difference Between a Leach Field Vs. a Drain Field In Septic?

      We may have heard the term leach field or drain field. We may wonder what the difference is between a leach field vs. drain fields in a septic system. They are two terms that define the same thing.

      The technical term is a leach field, but there is no difference between a leach field and a drain field. 

      Some call it a leach field, and some call it a drain field. It is referred to as a drain field because the liquid contaminants drain from the septic tank and into the ground. 

      Did you know?  A leach field has many different names. It is also called a drain field, a leaching bed, a filter bed, and a percolation bed.

      did you know what is a septic leach field

      Things To Know About The Leach Field Of Your Septic Tank.

      It’s up to us to maintain the leech field on our septic tank

      Damaging our leach lines can be expensive. Just like any drain, the leach lines require oxygen to flow. Pouring a concrete pad or driving a vehicle over a leach field can damage the perforated pipes or block the filtering holes.

      Livestock can also damage the PVC material. We should never let our animals graze on top of a drain field.

      We should take care when planting anything in the leach field. Tree roots can damage any part of our septic system. 

      Anything we flush down our drains that can’t decompose properly can eventually make its way out and clog the leach lines. 

      The majority of septic system problems are due to leach line malfunctions. We should check the functionality of our septic tank distribution box annually, at the very least. Any plumbing problems in our home could be from blocked or damaged leach lines.

      Repairing a leach field is a very costly repair. It’s crucial to maintain our septic tank by checking when it’s full and the leach lines themselves. 

      How Deep Down Is A Leach Field?

      The typical leech line is buried at eighteen inches and can be as deep as three feet.

      Leach Fields usually consist of multiple trenches that lay parallel in a flat-level area in our yard. These trenches are typically six feet apart and two feet wide. Because they are at a slope for drainage, the depth will vary throughout each pipe. 

      This video shows exactly how deep we should install a leach field.

      Final Thoughts On Leach Fields

      After our septic tank does its job with the solid waste, the final effluent product will seep into our soil naturally by following the leach lines. 

      A typical leach field can last up to fifty years but needs to be maintained regularly. While our septic tank breaks down the hard stuff, the liquid bi-product flows freely down the leach lines.

      Our best defense is to flush only the appropriate items down on drain. Don’t flush toilet paper with dyes or flushable wipes. These will eventually clog your system. Instead, use a septic safe toilet paper product.

      We also need to check and maintain our leach field regularly. 

      When we notice greener grass and increased plant growth around our septic tank, it is a good sign that our leach field is malfunctioning.  Compaction is the number one enemy of the perforated pipes in our leech system. 

      Leach And Drain Field FAQs

      What Is The Purpose Of A Leach Field?

      The purpose of a leach field is to transport the liquid by-product called effluent out of our septic tank. It filters into our soil naturally through rows of perforated pipes. 

      What Is The Difference Between A Septic Tank And A Leach Field?

      The septic tank is responsible for breaking down our solid waste. As the tank fills up, the liquids travel into the leach field. The leach field is responsible for filtering out the contaminants from the remaining wastewater.

      How Deep Down Is A Leach Field?

      Leach lines are buried as shallow as eighteen inches and can be as deep as three feet.

      Meet Your Plumbing Navigator

      Plumbing Navigator: plumbing advice

      About Plumbing Navigator

      We’re passionate about all things plumbing, and love sharing tips, “how-to”, and reviewing the latest products to help make your project a success!

      Learn More Plumbing Tips

      Want to tackle more plumbing projects? Check out these helpful guides!

      best water heater stand
      tankless water heater flush kit
      best mesh drain strainer
      Best Shower Drain Cover

      Got Plumbing Questions? Search For In-Depth Answers Below!

      About Plumbing Navigator

      We write about "all things plumbing," helping you navigate common questions, repairs, and the best plumbing products on the market.

      About Plumbing Navigator

      We write about “all things plumbing,” helping you navigate common questions, repairs, and the best plumbing products on the market.

      Recently Published Guides